Labels:text | font | screenshot | paper | document OCR: Modern reptiles (animals that have waterproof skin and lay eggs) cannot produce a wide range of sounds because they lack the sound-making parts, the vocal cords, found in the throats of mammals (animals that have hair and feed their young on milk) and in the syrinx in birds (animals that have feathers). Yet they can produce a range of hisses and roars by blowing air up the windpipe and out through the throat, nose, and mouth. Dinosaurs have been extinct for millions of years, and there is no way of knowing for certain whether they made sounds. However, there is some evidence to suggest that they did produce sounds. Parasaurolophus had a complex arrangement of tubes in its skull. By forcing air from its lungs through these tubes, Parasaurolophus may have been able to produce a low, bellowing sound. EDMONTOSAURUS Fossil skulls of Edmontosaurus show that it did not have a bony crest, but that it had deep grooves on either side of its nasal area. These may have been covered by loose flaps of skin that could be inflated to balloon out and amplify vibrations made in the nasal passages to produce loud, trumpet-like sounds. CORYTHOSAURUS Corythosaurus had a bony crest on its head. This dinosaur may have pushed air out of its lungs just hard enough to set the air flowing in a semicircular pattern through its nasal passages. In turn, this would have set up vibrations that probably produced a full, hornlike sound.
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